The present invention pertains to an improved water-based defoamer composition. The present invention more particularly relates to an improved water-based defoamer composition that has utility in the alcoholic fermentation of sugar cane juice and corn syrup.
Antifoaming compositions are materials used in the prevention, removal and control of unwanted foam. Unwanted fluid foams are made up of numerous tiny bubbles of a mechanical or chemical origin which are generated within a liquid and which rise and accumulate at the liquid surface faster than they decay.
The field in which unwanted foams are encountered are diverse. Foam problems can be found in polymerization, paint process, papermaking processes, oil drilling and refining operations, food preparation and textile dyeing operations. Liquid coolants, hydraulic fluids, lubricants, aviation fuels and gas absorption systems may foam with undesirable results under conditions of operation. If not properly controlled, foam can reduce equipment capacity and increase processing time and expense, and in some instances, cause other dangers.
Although foam can be controlled in some instances by making changes to the process itself, or by using mechanical defoaming equipment, chemical antifoam formulations have proven effective and economical.
Distilleries which use molasses or sugar cane juice as raw materials for ethanol production face several operational problems. One of the more serious problems is foam generation during this fermentative process.
To allow sucrose fermentation, it is necessary to decompose it to fructose and glucose, which are simpler sugars, according to the reaction;
C12H22O11+H2Oxe2x86x922C2H5OH+2CO2+56KCal
The components of the mixture under fermentation, composed mainly of sugars, electrolytes, proteins and acids, get concentrated in the air-liquid interface, generating an elastic foam.
The gases that are produced during the fermentation process due to their lower density relative to the liquid phase, rise to the surface and stretch the elastic film. As this film is relatively resistant to being broken, the gases remain in the top part of the liquid causing bubbles (i.e. foam) to form.
The formed foam must be rigorously controlled to avoid fermentation tank overflow, which could result in loss of broth, yeasts or ethanol.
The present inventors have discovered a water-based defoaming composition which has proven more effective than the synthetic wax and mineral oil based defoamers typically used in the fermentation industry.
The present invention provides for defoamer compositions having utility in alcoholic fermentations. The defoamer compositions are aqueous based and comprise polydimethylsiloxane oils, ethylene oxide/propylene oxide block copolymers and a silicone/silica blend.
Polydimethylsiloxanes have been employed in non-aqueous mediums such as residual petroleum stocks and crude oils as defoamers as taught in U.S. Pat. Nos. 3,700,587 and 4,082,690. Liquid organosilicon condensations products or polymers in combination with silane have been taught in U.S. Pat. No. 2,702,793 as defoamers in oils and antifreezes. Polyvinylalkoxysilanes and polyvinylalkylalkoxysilanes are taught in U.S. Pat. No. 2,862,885 to control foaming in petroleum-type oils, particularly those in the lubricating oil viscosity range.
U.S. Pat. No. 3,959,175 teaches an aqueous defoamer composition containing liquid polybutene. The defoamer composition can further comprise in part hydrophobic silica and silicone oils. U.S. Pat. No. 5,288,789 teaches the use of a condensate of alkylphenol and aldehyde that has been polyoxyalkylated to reduce foam in a fermentation broth.